Add pre-commit hook to check dask version consistency

[bdice]

Summary

• Adds a pre-commit hook that validates dask, dask-core, and distributed versions are consistent across dependencies.yaml, pyproject.toml, and conda/recipes/rapids-dask-dependency/recipe.yaml

This addresses the issue seen in #142 and #147 where the conda recipe was not updated when the dask version was changed in dependencies.yaml.

The hook:

• Uses only Python standard library (no external dependencies)
• Only runs when relevant files are modified
• Provides clear error messages showing which files have mismatched versions

[bdice]

This will fail checks until #147 is forward-merged.

[jakirkham]

Thanks Bradley! 🙏

So this should fail already as they are inconsistent currently

rapids-dask-dependency/dependencies.yaml

Lines 35 to 40 in 8aa3e89

	python_run:
	common:
	- output_types: [pyproject, requirements]
	packages:
	- dask==2026.1.1
	- distributed==2026.1.1

rapids-dask-dependency/pyproject.toml

Lines 14 to 17 in 8aa3e89

	dependencies = [
	"dask==2026.1.1",
	"distributed==2026.1.1",
	] # This list was generated by `rapids-dependency-file-generator`. To make changes, edit dependencies.yaml and run `rapids-dependency-file-generator`.

rapids-dask-dependency/conda/recipes/rapids-dask-dependency/recipe.yaml

Lines 27 to 30 in 8aa3e89

	run:
	- dask ==2025.12.0
	- dask-core ==2025.12.0
	- distributed ==2025.12.0

[bdice]

Output:

check dask version consistency...........................................Failed
- hook id: check-dask-versions
- exit code: 1

ERROR: Dask version inconsistency detected!

Dask version mismatch:
  dependencies.yaml: 2026.1.1
  pyproject.toml: 2026.1.1
  recipe.yaml: 2025.12.0
  recipe.yaml (dask-core): 2025.12.0
Distributed version mismatch:
  dependencies.yaml: 2026.1.1
  pyproject.toml: 2026.1.1
  recipe.yaml: 2025.12.0

All dask, dask-core, and distributed versions must be identical across:
  - dependencies.yaml
  - pyproject.toml
  - conda/recipes/rapids-dask-dependency/recipe.yaml

https://github.com/rapidsai/rapids-dask-dependency/actions/runs/21461284750/job/61814178623?pr=148

[pentschev]

This is a great idea, thanks @bdice ! I now have a new, more challenging ask based on this idea, can we proliferate this idea and do the same with our dependencies.yaml and our conda recipe.yaml files? It is more challenging because there's not always an equivalency, sometimes we need to dumb down pip packages due to missing packages in PyPI (for example, OpenMPI and NUMA), and package names are not always consistent, so I'm uncertain whether that can be done (programmatically at least).

[pentschev]

/merge

[bdice]

can we proliferate this idea and do the same with our dependencies.yaml and our conda recipe.yaml files?

Great question. tl;dr We haven't implemented this yet. It is tracked in rapidsai/dependency-file-generator#7. This was blocked for a long time due to the meta.yaml format not being especially conducive to generation, but it may be possible now that we've migrated to rattler-build and recipe.yaml.